﻿Shader "Example01/11溶解-软裁剪"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _DissolveTex("DissolveTex",2D) ="white" {}
        _Value("Value",Range(0,1)) = 0
        _Soft("Soft",Range(0,10)) = 0
    }
    SubShader
    {
        Tags
        { 
            "Queue" = "Transparent"
            "RenderType" = "Transparent"
            "PreviewType" ="Plane"
        }
        
        Cull Off
        Lighting Off
        ZWrite Off
        Blend SrcAlpha OneMinusSrcAlpha

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            sampler2D _MainTex;
            sampler2D _DissolveTex;
            float _Value;
            float _Soft;

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = UnityObjectToClipPos(v.vertex);
                o.uv = v.uv;
                return o;
            }

            fixed4 frag (v2f i) : SV_Target
            {
                fixed4 col = tex2D(_MainTex, i.uv);
                fixed3 dissolveCol = tex2D(_DissolveTex, i.uv);
                // 把数值转换到0-2
                dissolveCol += 1;
                // 属性值翻转到0-2
                fixed value = _Value *-2;
                // 通过加减控制黑白颜色
                dissolveCol += value;
                // 计算使得更锐利
                dissolveCol =lerp((ldexp(dissolveCol,_Soft)),0,value);
                // 控制在0 和 1 之间
                fixed alphaCol = saturate(dissolveCol) * col.a;
                return fixed4(col.rgb ,alphaCol); 
            }
            ENDCG
        }
    }
}